Fluid management is important in many fields such as in domestic fields, scientific fields, plants and in the medical field. In the medical field, in particular, the accuracy of fluid flow measurements and fluid management can be essential. There are many methods and devices for measuring fluid flow when the flow is a continuous flow; however in the non-continuous flow regime such as drops, lack of accurate measurement techniques is prominent.
Usually, volumetric drops flow or other non-continuous flow of fluids is measured using collecting means or optical counters (for drops). An example for an optical counter is disclosed in U.S. Pat. No. 4,314,484 “Self-Compensating Optical drop Count Apparatus for Measuring Volumetric Fluid Flow” by Bowman and filed in 1979. The patent discloses a self-compensating optical drop count apparatus for measuring volumetric fluid flow by optically counting the number of drops that pass through a drop chamber. Optical counting circuitry is designed to count each drop only once. Another counter is disclosed in U.S. Pat. No. 6,640,649 “Droplet Counter for Low Flow Rates” by Paz et al. This low flow metering device for measuring the flow of an amount of fluid exceeding 0.05 ml, in which a first chamber has an inlet and an outlet in fluid communication with a second chamber, the first chamber containing an element creating laminar flow. An electronic system is positioned in the second chamber below a drop generator for counting the passage of each droplet existing therefrom, and an information processing unit is connected to the electronic system for receiving and recording information.
These means as well as other means for fluid management bear inherent mass errors that accumulatively may generate massive mistakes in the result of the measurement. Such systems for fluid management in which non-continuous measurements are performed are used in many disciplines such as scientific fields or medical fields as mentioned herein above, in which mistakes may have serious and hazardous outcomes.
The inventors of the present invention disclosed an invention that overcomes the disadvantages of existing patents and devices in this field. The invention is disclosed in PCT/IL2004/000407 published as WO/2004/101121 and describes an efficient and accurate apparatus for measuring volumetric or mass flow of fluid. However, an uncomplicated and cost effective apparatus is still needed in the art.